Rheostat.



' T. RHODUS.

RHEOSTAT.

APPLICATION FILED DEC.26, 1914.

1,154,728. PatentedSept. 28, 1915.

citizen of the United THOMAS mIoDUS, or cI'IIoAGo, ILLINOIS.

EI'IEoSTAT.

T all whom it may concern.'

Be it known that I, THoMAs RHoDUs, a States of America, and a resident of Chicago, in the county of Cook, State'of Illinois, have invented certainnew and useful Improvements in Rheostats, of'which the following is a specification. f

This invention relates to that typeof rheostats in which the resistance element is formed by a spiral winding of wire disposed in con.

centric-relation to a centrally arranged and manually actuated shaft carrying the'adjustable contact member of the apparatus, an eX- amplevof which forms the subjectmatter of I my-prior Patent No. 1,053,219, dated F ebruary 18, 1913. And the present improvement I has for its object, to provide a simple and efficient structuralformation and association of parts whereby an extended-contact is attained between the adjustable Contact niember and -one or more adjacent 'individual wire, windings lof the Stationary resistance member, with an avoidance of wear upon the active surface of such windings, and the change`in the electrical resistance thereof due to such wear, all as will hereinafter more fully appear.

In the .accompanying drawings; Figure 1, isa sectional plan view of. a rheostat, embodying thepreferred form of the present invention. Fig. 2, ispa detail perspective view of the adjustable vcontact member and its accessories. Figs..3 and 4, are detail perspectivel views illustrating modified forms of the adjustable contact imember and its accessories.

'Similar reference numeralsindicate 'likeparts inthe severalviews.

Referring to drawing, 1 represents the supporting base or spider having a plurality of radially projecting feet 2, by which it is attached to the surface of a bench, wall or` other support.

` 3 designates the inclosing shell of tlie'avpa` paratus, of any usual and suitably oriiced form which permits of acirculation .of air to ventilate and carry volf the .heat'generated in the actual use of the appliance. Such shell is preferably ,of a circular form and secured in place by means of attaching screwspassing through the shell and screwing into a circularly disposed series of lugs 4 on the frame 1, aforesaid.

5- designates a slab or bar of insulatlng material secured to the upper surface of the Specification of Letters Patent.

Patented sept. as, 1915.

Application led December 26, 1914'. Serial N o. 879,009.

framel, to form an insulating support for the sta ionary resistance element and its accessories hereinafter described.

6 designates the resistance element ofthe present structure, formed by a series of fiat open spiral windings of resistance wire,

wound upon an insulating core, as in my aforesaid Patent No. 1,053,219. And as in sald patented construction, said core will be Dfan open ring shape,

ends secured toa supportin bracket 7 at- 'tached to the`insulating sla 5, above described, and with said core and its resistance wire arranged in concentric relation to the enter or aXls of the rheostat `as shown in ed to afford. a journal bearing for the axially arranged revoluble shaft which carries the adjustable contact member of the' rheostat.

- 9 designates the revoluble shaft, above referred to, and which is provided with a-suitableoperating handle for convenient man-v ua'l adjustment-in actual use.

' '10' designates a radially disposed arm or .member, provided at its outer end with a carrying head or yoke 11, to which is jourt naled a roller or drum` 12, having rolling contact with the inner surface of the stationary resistance element 6, the associated Ajoarts just described constituting the movable contact element of the rheostat. The described construction admits of theuse of a contact roller or drum of ample length to afford a with overlapping 8 designates a bearing hub or' neck secured centrally to the insulating slab 5, and adaptcorrespondingv degree of electrical contact with one or more individual strands of the spirally Woundv resistance wire of the `stationary resistance element 6, In actual use.

At 'its inner-endthel arm or member 10,

is slidingly carried by the movable shaft 9,

cis

aforesaid, and a resilient Aoutward tendency is imparted to said arm or member 10, by a spring 13, hereinafter described. The sliding connection between the arm 10 and the shaft 9 may be effected by`various detail structural means. In the construction shown in Fig. 3, the shaft 9 is provided with a fixed lateral arm 10 upon which the carrying head or yoke 11, aforesaid, is slidingly mounted by means of a sleeve eXtension 11 that is slotted longitudinally to receive a guide pin 10 of said lateral arm 10 adapted to prevent any turning movement of the yoke 1l upon said lateral arm. In the construction illustratedy in Fig. 4, the revolubleshaft 9 is formed with a transverse guide 9 which receives an inner end of the -arm 10 formed to slidingly fit the said oritice 9 as shown. With such construction means is required to prevent any rotation of the guiding end of the arm 10 in the orifice 9, and this is attained'by 4a laterally arranged fixed arm 111 on the shaft 9, having sliding engagement at its outer end between a pair of depending lugs or prongs 11 on the yoke 11, aforesaid.

The ,preferred means for attaining said slidingconnection is illustrated in Figs. 1 and 2, and comprises the formation of the shaft 9 in two sections disposed in separated axial alinement and connected together by a yoke 15, as shown.

16 designates a C shaped bracket securedin angular relation to the yoke 15, and having its arms formed with alined guide orifices for thereception of the inner portion of the arm 10, aforesaid, andwhich inner portion is formed to slidingly fit said oriices as shown.

The spring 13, before mentioned, may have any usual form and arrangement but is preferably of the coiled form shown, and arranged to encircle the arm 10, as illustrated in the various figures of the drawings.

The modified constructions illustrated in Figs. 3 and 4, are made the subject matter of a separate application for Letters Patent Serial No. 16,546, filed March 24th, 1915.

17 and 18 designate binding posts secured to an outer portion of the insulating slab 5, aforesaid and h-aving connection respectively with the stationary resistance element 6, and with the movable contact element 10,

' 12, as shown in Fig. 1. l

Having thus fully described my said invention what I claim as new and desire to secure by Letters Patent, is

\ V1. In a rheostat, the combination of an insulating support a ring shape resistance element formedin the main of a resistance wire Wound into an open series of convolutions, a rolling Contact element having contact with kthe inner Wall of said resistance element, a centrally `arranged revoluble shaft, an arm slidingly associatedl with said shaft and carrying at its outer end the rolling contact element aforesaid, and means for yieldingly forcing said arm outward, substantially as set forth. I .s

2. In a rheostat, the combination of an insulating support, a ring shape-resistance element formed in the main of a resistance wire wound into an open series of convolutions, a rolling contact element having contact with the inner wall of said resistance element, a centrally arranged revoluble shaft, an arm slidingly associated with said shaft and carrying at its outer end the rolling contact element aforesaid, and a. spring encircling said arm and adapted to force the same outwardly, substantially as set forth. y

3. In a rheostat, the combination of an insulating support, a ring shape resistance element formed in the main of a resistance Wire Wound into an open series of convolu tions, a rolling Contact element having coni tact with the inner wall of said resistance element, a centrally arranged revoluble shaft formed in spaced and alined sections, a yoke connecting said sections together, a guide bracket associated With said yoke, an arm slidinglymounted in said bracket and carrying at its outer end the rolling contact element aforesaid, and means for yieldingly forcing said arm outward, substantially as set forth.

4. In a rheostat, the combination of a supporting frame, a reticulated inclosing casing carried by said frame, an insulating slab mounted on said frame, a ring shaped resistance element formed in the main of resistance Wire Wound in a flat open series of convolutions, a rolling contact element having contact with the inner wall of said re` sistance element, a centrally arranged revoluble shaft, an arm slidingly associated with said shaft and carrying at its outer end the rolling contact element aforesaid, and means for yieldingly forcing said arm outward, substantially as set forth. I

5. In a rheostat, the combination of a supporting frame, a reticulated inclosing casing carried by said frame, an insulating slab mounted on said frame, a ring shaped resistance element formed in the main ofa resistance wire Wound into a fiat open series of convolutions, a rolling contact element having contact with the inner Wall of said resistance element, a centrally arranged rev* oluble shaft, an arm slidingly associated with said shaft and carrying at its outer end the rolling contact element aforesaid, and a spring encircling said arm and adapted to force the same outwardly, substantially as set forth.

6. In a rheostat, the combination of a supporting frame, a reticulated inclosing casing carried by said frame, an insulating slab mounted onsaid frame, a ring shaped re'- sistance element formed in the main of a resistance Wire woundinto a flat open series of jconvolutions, a rolling contact element having contact withntheinner wall of said l resistance element, a centrally arranged revoluble shaft formed in spaced and alined sections, a yoke connecting saidsections together, a guide'bracket associated with said yoke, an armnslidingly mounted in said bracket and carrying at its outer end the rolling contacte/lement aforesaid, and means for yieldingly forcing said arm outward,

substantially as set forth. y

7'. In a rheostat, the combination of an insulating support, a ring shaped resistance element'fformed `in the main of a resistance wire Wound into anopen series of convoluyieldingly forcin said contact element olit-v Ward,A substantial y as set forth.

8. l. In ,a rheostat, thev combination of a curved resistance element formed in the main of a resistance wire wound into an open series of convolutions, a rolling lcontact element having contact with the inner 1.5

surface of the resistance element'a lcentrally arranged revoluble shaft, and an'expansible carrying means connected at its inner end to said revoluble shaft and provided at its outer end with a journal bearing for lsaid 20 rollirlig contact element', substantially as set fort Signed at Chicago, Illinois, this 22nd day of December, 1914. i

i THOMAS RHODUS. Witnesses:

'ROBERT BURNs, Hyun W. Panca. 

